This invention relates in general to apparatus for working on a layup of sheet material and deals more particularly with an improved apparatus for applying a substance to a plurality of individual sheets of material arranged in vertically stacked relation to form a layup and at a predetermined location on each of the sheets.
In the processing of sheet material used in the production of garments, upholstery, and like products, sheet material components from which a product is made must often be marked, for various purposes. In the production of a garment, for example, the positions of buttons, buttonholes, darts and the like must be marked on component parts of the garment to facilitate subsequent garment assembly operations. To assure uniformity of the end product, it is generally desirable that the various sheets of material, or the components which are cut from these sheets, be marked, as required, in a single operation while the sheets are in layup form and before separation. Automated apparatus of the aforedescribed general type has heretofore been used for this purpose. A typical apparatus for marking a layup is illustrated and described n U.S. Pat. No. 3,731,648 to Gerber et al, assigned to the assignee of the present application, and includes an elongated hollow needed-like tool for penetrating a layup and through which fluid is ejected as the tool is withdrawn from the layup. Such apparatus may also be used to deposit adhesive at selected locations within a layup to control fraying or to temporarily adhere together the individual sheets which comprise the layup so that the layup, the individual parts cut from the layup and/or the resulting scrap material produced by the cutting operation may be handled as a unit. Such apparatus has proven generally satisfactory for processing a layup of porous fabric, or the like, which is easily penetrated by such a tool, however, a problem is encountered where the apparatus is used to process a layup of heavy fabric or dense non-porous material which offers greater resistance to tool penetration. The tool may, for example, be laterally deflected as it is pushed downwardly through the layup causing inaccurate marking and resulting in non-uniform end products. Where such material resistance is encountered the speed at which the marking operation may be performed is also substantially reduced. The present invention is concerned with aforesaid problems.